将名称和历史属性添加到 2D 粒子模拟
Adding name and history attribute to 2D particle simulation
我正在尝试创建一个模拟粒子在 2D 盒子中碰撞的程序，但每个粒子都标有一个随机的 5 个字符串名称，并且每个碰撞都在一个列表中沿着每个粒子进行跟踪。所以在模拟之后，我想要一个列表，列出它击中了哪些粒子的每个粒子。我分叉了这个很棒的模拟 https://github.com/xnx/collision 并将名称和历史属性添加到粒子 class。但是，每当我尝试访问 .name 或 .history 时，我的内核就会死掉。输出显示：
Kernel died, restarting
Restarting kernel...
失败发生在 handle_collisions 函数（第 197 行）中，或者每当我尝试访问历史记录或名称时，所以我对名称和历史属性的实现一定有问题。我还尝试在 init_particles 函数而不是 place_particles 中实例化名称和历史记录，但结果相同。我不确定如何正确实施它们。感谢您的帮助。
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.patches import Circle
from matplotlib import animation
from itertools import combinations
import random
import string
class Particle:
"""A class representing a two-dimensional particle."""
def __init__(self, x, y, vx, vy, name, history, radius=0.01, styles=None):
"""Initialize the particle's position, velocity, name, history and radius.
Any key-value pairs passed in the styles dictionary will be passed
as arguments to Matplotlib's Circle patch constructor.
"""
self.r = np.array((x, y))
self.v = np.array((vx, vy))
self.radius = radius
self.mass = self.radius**2
self.styles = styles
if not self.styles:
# Default circle styles
self.styles = {'edgecolor': 'b', 'fill': False}
# For convenience, map the components of the particle's position and
# velocity vector onto the attributes x, y, vx and vy.
@property
def x(self):
return self.r[0]
@x.setter
def x(self, value):
self.r[0] = value
@property
def y(self):
return self.r[1]
@y.setter
def y(self, value):
self.r[1] = value
@property
def vx(self):
return self.v[0]
@vx.setter
def vx(self, value):
self.v[0] = value
@property
def vy(self):
return self.v[1]
@vy.setter
def vy(self, value):
self.v[1] = value
@property
def history(self):
return self.history
@history.setter
def history(self,value):
self.history=value
@property
def name(self):
return self.name
@name.setter
def name(self,value):
self.name=value
def overlaps(self, other):
"""Does the circle of this Particle overlap that of other?"""
return np.hypot(*(self.r - other.r)) < self.radius + other.radius
def draw(self, ax):
"""Add this Particle's Circle patch to the Matplotlib Axes ax."""
circle = Circle(xy=self.r, radius=self.radius, **self.styles)
ax.add_patch(circle)
return circle
def advance(self, dt):
"""Advance the Particle's position forward in time by dt."""
self.r += self.v * dt
class Simulation:
"""A class for a simple hard-circle molecular dynamics simulation.
The simulation is carried out on a square domain: 0 <= x < 1, 0 <= y < 1.
"""
ParticleClass = Particle
def __init__(self, n, radius=0.01, styles=None):
"""Initialize the simulation with n Particles with radii radius.
Each particle is initialized with a 10 letter string name and an empty history.
radius can be a single value or a sequence with n values.
Any key-value pairs passed in the styles dictionary will be passed
as arguments to Matplotlib's Circle patch constructor when drawing
the Particles.
"""
self.init_particles(n, radius, styles)
self.dt = 0.01
def place_particle(self, rad, styles):
# Choose x, y so that the Particle is entirely inside the
# domain of the simulation.
x, y = rad + (1 - 2*rad) * np.random.random(2)
# Choose a random velocity (within some reasonable range of
# values) for the Particle.
vr = 0.1 * np.sqrt(np.random.random()) + 0.05
vphi = 2*np.pi * np.random.random()
vx, vy = vr * np.cos(vphi), vr * np.sin(vphi)
name = self.assignname
history = []
particle = self.ParticleClass(x, y, vx, vy, name, history, rad, styles)
# Check that the Particle doesn't overlap one that's already
# been placed.
for p2 in self.particles:
if p2.overlaps(particle):
break
else:
self.particles.append(particle)
return True
return False
def assignname(self):
letters = string.ascii_lowercase
name=''.join(random.choice(letters) for i in range(5))
return name
def init_particles(self, n, radius, styles=None):
"""Initialize the n Particles of the simulation.
Positions and velocities are chosen randomly; radius can be a single
value or a sequence with n values.
"""
try:
iterator = iter(radius)
assert n == len(radius)
except TypeError:
# r isn't iterable: turn it into a generator that returns the
# same value n times.
def r_gen(n, radius):
for i in range(n):
yield radius
radius = r_gen(n, radius)
self.n = n
self.particles = []
for i, rad in enumerate(radius):
# Try to find a random initial position for this particle.
while not self.place_particle(rad, styles):
pass
def change_velocities(self, p1, p2):
"""
Particles p1 and p2 have collided elastically: update their
velocities.
"""
m1, m2 = p1.mass, p2.mass
M = m1 + m2
r1, r2 = p1.r, p2.r
d = np.linalg.norm(r1 - r2)**2
v1, v2 = p1.v, p2.v
u1 = v1 - 2*m2 / M * np.dot(v1-v2, r1-r2) / d * (r1 - r2)
u2 = v2 - 2*m1 / M * np.dot(v2-v1, r2-r1) / d * (r2 - r1)
p1.v = u1
p2.v = u2
def handle_collisions(self):
"""Detect and handle any collisions between the Particles.
When two Particles collide, they do so elastically: their velocities
change such that both energy and momentum are conserved.
"""
# We're going to need a sequence of all of the pairs of particles when
# we are detecting collisions. combinations generates pairs of indexes
# into the self.particles list of Particles on the fly.
#particles share history when they collide
pairs = combinations(range(self.n), 2)
for i,j in pairs:
if self.particles[i].overlaps(self.particles[j]):
self.change_velocities(self.particles[i], self.particles[j])
#FAILS HERE
#self.particles[i].history.append(self.particles[j].name)
#self.particles[j].history.append(self.particles[i].name)
def handle_boundary_collisions(self, p):
"""Bounce the particles off the walls elastically."""
if p.x - p.radius < 0:
p.x = p.radius
p.vx = -p.vx
if p.x + p.radius > 1:
p.x = 1-p.radius
p.vx = -p.vx
if p.y - p.radius < 0:
p.y = p.radius
p.vy = -p.vy
if p.y + p.radius > 1:
p.y = 1-p.radius
p.vy = -p.vy
def apply_forces(self):
"""Override this method to accelerate the particles."""
pass
def advance_animation(self):
"""Advance the animation by dt, returning the updated Circles list."""
for i, p in enumerate(self.particles):
p.advance(self.dt)
self.handle_boundary_collisions(p)
self.circles[i].center = p.r
self.handle_collisions()
self.apply_forces()
return self.circles
def advance(self):
"""Advance the animation by dt."""
for i, p in enumerate(self.particles):
p.advance(self.dt)
self.handle_boundary_collisions(p)
self.handle_collisions()
self.apply_forces()
def init(self):
"""Initialize the Matplotlib animation."""
self.circles = []
for particle in self.particles:
self.circles.append(particle.draw(self.ax))
return self.circles
def animate(self, i):
"""The function passed to Matplotlib's FuncAnimation routine."""
self.advance_animation()
return self.circles
def setup_animation(self):
self.fig, self.ax = plt.subplots()
for s in ['top','bottom','left','right']:
self.ax.spines[s].set_linewidth(2)
self.ax.set_aspect('equal', 'box')
self.ax.set_xlim(0, 1)
self.ax.set_ylim(0, 1)
self.ax.xaxis.set_ticks([])
self.ax.yaxis.set_ticks([])
def save_or_show_animation(self, anim, save, filename='collision.mp4'):
if save:
Writer = animation.writers['ffmpeg']
writer = Writer(fps=10, bitrate=1800)
anim.save(filename, writer=writer)
else:
plt.show()
def do_animation(self, save=False, interval=1, filename='collision.mp4'):
"""Set up and carry out the animation of the molecular dynamics.
To save the animation as a MP4 movie, set save=True.
"""
self.setup_animation()
anim = animation.FuncAnimation(self.fig, self.animate,
init_func=self.init, frames=800, interval=interval, blit=True)
self.save_or_show_animation(anim, save, filename)
if __name__ == '__main__':
nparticles = 20
radii = .02
styles = {'edgecolor': 'C0', 'linewidth': 2, 'fill': None}
sim = Simulation(nparticles, radii, styles)
sim.do_animation(save=False)
我发现您的代码中存在两个直接问题。
首先：您确实将历史添加为 Particle.__init__ 参数，但您从未初始化 属性 本身。
添加如下内容：
def __init__(self, x, y, vx, vy, name, history, radius=0.01, styles=None):
self._history = history
更大的问题：你的@属性定义中有一个无限递归：
@property
def history(self):
return self.history
@history.setter
def history(self,value):
self.history=value
所以在你的 getter 中你调用了 history 你调用了它自己 return self.history 它将自己循环直到程序崩溃。
将内部 属性 重命名为 _history:
@property
def history(self):
return self._history
@history.setter
def history(self,value):
self._history=value
我正在尝试创建一个模拟粒子在 2D 盒子中碰撞的程序，但每个粒子都标有一个随机的 5 个字符串名称，并且每个碰撞都在一个列表中沿着每个粒子进行跟踪。所以在模拟之后，我想要一个列表，列出它击中了哪些粒子的每个粒子。我分叉了这个很棒的模拟 https://github.com/xnx/collision 并将名称和历史属性添加到粒子 class。但是，每当我尝试访问 .name 或 .history 时，我的内核就会死掉。输出显示：
Kernel died, restarting
Restarting kernel...
失败发生在 handle_collisions 函数（第 197 行）中，或者每当我尝试访问历史记录或名称时，所以我对名称和历史属性的实现一定有问题。我还尝试在 init_particles 函数而不是 place_particles 中实例化名称和历史记录，但结果相同。我不确定如何正确实施它们。感谢您的帮助。
import numpy as np
import matplotlib.pyplot as plt
from matplotlib.patches import Circle
from matplotlib import animation
from itertools import combinations
import random
import string
class Particle:
"""A class representing a two-dimensional particle."""
def __init__(self, x, y, vx, vy, name, history, radius=0.01, styles=None):
"""Initialize the particle's position, velocity, name, history and radius.
Any key-value pairs passed in the styles dictionary will be passed
as arguments to Matplotlib's Circle patch constructor.
"""
self.r = np.array((x, y))
self.v = np.array((vx, vy))
self.radius = radius
self.mass = self.radius**2
self.styles = styles
if not self.styles:
# Default circle styles
self.styles = {'edgecolor': 'b', 'fill': False}
# For convenience, map the components of the particle's position and
# velocity vector onto the attributes x, y, vx and vy.
@property
def x(self):
return self.r[0]
@x.setter
def x(self, value):
self.r[0] = value
@property
def y(self):
return self.r[1]
@y.setter
def y(self, value):
self.r[1] = value
@property
def vx(self):
return self.v[0]
@vx.setter
def vx(self, value):
self.v[0] = value
@property
def vy(self):
return self.v[1]
@vy.setter
def vy(self, value):
self.v[1] = value
@property
def history(self):
return self.history
@history.setter
def history(self,value):
self.history=value
@property
def name(self):
return self.name
@name.setter
def name(self,value):
self.name=value
def overlaps(self, other):
"""Does the circle of this Particle overlap that of other?"""
return np.hypot(*(self.r - other.r)) < self.radius + other.radius
def draw(self, ax):
"""Add this Particle's Circle patch to the Matplotlib Axes ax."""
circle = Circle(xy=self.r, radius=self.radius, **self.styles)
ax.add_patch(circle)
return circle
def advance(self, dt):
"""Advance the Particle's position forward in time by dt."""
self.r += self.v * dt
class Simulation:
"""A class for a simple hard-circle molecular dynamics simulation.
The simulation is carried out on a square domain: 0 <= x < 1, 0 <= y < 1.
"""
ParticleClass = Particle
def __init__(self, n, radius=0.01, styles=None):
"""Initialize the simulation with n Particles with radii radius.
Each particle is initialized with a 10 letter string name and an empty history.
radius can be a single value or a sequence with n values.
Any key-value pairs passed in the styles dictionary will be passed
as arguments to Matplotlib's Circle patch constructor when drawing
the Particles.
"""
self.init_particles(n, radius, styles)
self.dt = 0.01
def place_particle(self, rad, styles):
# Choose x, y so that the Particle is entirely inside the
# domain of the simulation.
x, y = rad + (1 - 2*rad) * np.random.random(2)
# Choose a random velocity (within some reasonable range of
# values) for the Particle.
vr = 0.1 * np.sqrt(np.random.random()) + 0.05
vphi = 2*np.pi * np.random.random()
vx, vy = vr * np.cos(vphi), vr * np.sin(vphi)
name = self.assignname
history = []
particle = self.ParticleClass(x, y, vx, vy, name, history, rad, styles)
# Check that the Particle doesn't overlap one that's already
# been placed.
for p2 in self.particles:
if p2.overlaps(particle):
break
else:
self.particles.append(particle)
return True
return False
def assignname(self):
letters = string.ascii_lowercase
name=''.join(random.choice(letters) for i in range(5))
return name
def init_particles(self, n, radius, styles=None):
"""Initialize the n Particles of the simulation.
Positions and velocities are chosen randomly; radius can be a single
value or a sequence with n values.
"""
try:
iterator = iter(radius)
assert n == len(radius)
except TypeError:
# r isn't iterable: turn it into a generator that returns the
# same value n times.
def r_gen(n, radius):
for i in range(n):
yield radius
radius = r_gen(n, radius)
self.n = n
self.particles = []
for i, rad in enumerate(radius):
# Try to find a random initial position for this particle.
while not self.place_particle(rad, styles):
pass
def change_velocities(self, p1, p2):
"""
Particles p1 and p2 have collided elastically: update their
velocities.
"""
m1, m2 = p1.mass, p2.mass
M = m1 + m2
r1, r2 = p1.r, p2.r
d = np.linalg.norm(r1 - r2)**2
v1, v2 = p1.v, p2.v
u1 = v1 - 2*m2 / M * np.dot(v1-v2, r1-r2) / d * (r1 - r2)
u2 = v2 - 2*m1 / M * np.dot(v2-v1, r2-r1) / d * (r2 - r1)
p1.v = u1
p2.v = u2
def handle_collisions(self):
"""Detect and handle any collisions between the Particles.
When two Particles collide, they do so elastically: their velocities
change such that both energy and momentum are conserved.
"""
# We're going to need a sequence of all of the pairs of particles when
# we are detecting collisions. combinations generates pairs of indexes
# into the self.particles list of Particles on the fly.
#particles share history when they collide
pairs = combinations(range(self.n), 2)
for i,j in pairs:
if self.particles[i].overlaps(self.particles[j]):
self.change_velocities(self.particles[i], self.particles[j])
#FAILS HERE
#self.particles[i].history.append(self.particles[j].name)
#self.particles[j].history.append(self.particles[i].name)
def handle_boundary_collisions(self, p):
"""Bounce the particles off the walls elastically."""
if p.x - p.radius < 0:
p.x = p.radius
p.vx = -p.vx
if p.x + p.radius > 1:
p.x = 1-p.radius
p.vx = -p.vx
if p.y - p.radius < 0:
p.y = p.radius
p.vy = -p.vy
if p.y + p.radius > 1:
p.y = 1-p.radius
p.vy = -p.vy
def apply_forces(self):
"""Override this method to accelerate the particles."""
pass
def advance_animation(self):
"""Advance the animation by dt, returning the updated Circles list."""
for i, p in enumerate(self.particles):
p.advance(self.dt)
self.handle_boundary_collisions(p)
self.circles[i].center = p.r
self.handle_collisions()
self.apply_forces()
return self.circles
def advance(self):
"""Advance the animation by dt."""
for i, p in enumerate(self.particles):
p.advance(self.dt)
self.handle_boundary_collisions(p)
self.handle_collisions()
self.apply_forces()
def init(self):
"""Initialize the Matplotlib animation."""
self.circles = []
for particle in self.particles:
self.circles.append(particle.draw(self.ax))
return self.circles
def animate(self, i):
"""The function passed to Matplotlib's FuncAnimation routine."""
self.advance_animation()
return self.circles
def setup_animation(self):
self.fig, self.ax = plt.subplots()
for s in ['top','bottom','left','right']:
self.ax.spines[s].set_linewidth(2)
self.ax.set_aspect('equal', 'box')
self.ax.set_xlim(0, 1)
self.ax.set_ylim(0, 1)
self.ax.xaxis.set_ticks([])
self.ax.yaxis.set_ticks([])
def save_or_show_animation(self, anim, save, filename='collision.mp4'):
if save:
Writer = animation.writers['ffmpeg']
writer = Writer(fps=10, bitrate=1800)
anim.save(filename, writer=writer)
else:
plt.show()
def do_animation(self, save=False, interval=1, filename='collision.mp4'):
"""Set up and carry out the animation of the molecular dynamics.
To save the animation as a MP4 movie, set save=True.
"""
self.setup_animation()
anim = animation.FuncAnimation(self.fig, self.animate,
init_func=self.init, frames=800, interval=interval, blit=True)
self.save_or_show_animation(anim, save, filename)
if __name__ == '__main__':
nparticles = 20
radii = .02
styles = {'edgecolor': 'C0', 'linewidth': 2, 'fill': None}
sim = Simulation(nparticles, radii, styles)
sim.do_animation(save=False)
我发现您的代码中存在两个直接问题。
首先：您确实将历史添加为 Particle.__init__ 参数，但您从未初始化 属性 本身。
添加如下内容：
def __init__(self, x, y, vx, vy, name, history, radius=0.01, styles=None):
self._history = history
更大的问题：你的@属性定义中有一个无限递归：
@property
def history(self):
return self.history
@history.setter
def history(self,value):
self.history=value
所以在你的 getter 中你调用了 history 你调用了它自己 return self.history 它将自己循环直到程序崩溃。
将内部 属性 重命名为 _history:
@property
def history(self):
return self._history
@history.setter
def history(self,value):
self._history=value